#define _USE_MATH_DEFINES
#include <cassert>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <queue>
#include <stack>
#include <list>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <algorithm>
#include <complex>
#include <cmath>
#include <numeric>
#include <bitset>
#include <functional>
#include <random>
#include <ctime>
using namespace std;
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
const char* comma = strchr(names + 1, ',');
cerr.write(names, comma - names) << ": " << arg1 << " |";
__f(comma + 1, args...);
}
typedef long long int64;
typedef pair<int, int> ii;
const int INF = 1 << 29;
const int MOD = 1e9 + 7;
const int N = 2e3 + 10;
int dp[N][N];
void add(int& x, int y) {
x += y;
if (x >= MOD) x -= MOD;
}
int n, s, t;
int solve(int at, int k) {
// trace(at, k);
if (at == n - 1) return k == 0 ? 1 : 0;
int& ret = dp[at][k];
if (ret >= 0) return ret;
ret = 0;
if (at == s) {
// add left
add(ret, solve(at + 1, k));
// add left and touch a component
if (k > 0) add(ret, (int64)k * solve(at + 1, k - 1) % MOD);
return ret;
}
if (at == t) {
// add right
add(ret, solve(at + 1, k));
// add right and touch a component
if (k > 0) add(ret, (int64)k * solve(at + 1, k - 1) % MOD);
return ret;
}
// connect left end and a component
if (at > s && k > 0) add(ret, (int64)k * solve(at + 1, k - 1) % MOD);
// connect right end and a component
if (at > t && k > 0) add(ret, (int64)k * solve(at + 1, k - 1) % MOD);
// new component
add(ret, solve(at + 1, k + 1));
// connect 2 components
if (k >= 2) add(ret, (int64)k * (k - 1) * solve(at + 1, k - 1) % MOD);
return ret;
}
int main() {
scanf("%d%d%d", &n, &s, &t);
--s; --t;
memset(dp, 255, sizeof(dp));
int ret = solve(0, 0);
printf("%d\n", ret);
return 0;
}
